/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
int sumOfLeftLeaves(struct TreeNode* root)
{
    int sum=0;
    if(root)
    {
        if(root->left)
        {
            if(!root->left->left&&!root->left->right)
            {
                sum+=root->left->val;
            }
            else
            {
                sum+=sumOfLeftLeaves(root->left);
            }
        }
        if(root->right)
        {
            sum+=sumOfLeftLeaves(root->right);
        }
    }
    return sum;
}